The use of single stand reversing mills for cold rolling strip-shaped rolling material is well known. In such single stand reversing mills, up to approximately 450,000 tons per year of hot rolled strip can be cold rolled. If the steel plant has a higher output of hot rolled strips, then any hot rolled strips exceeding the approximately 450,000 tons per year yield could not be cold rolled and a second single stand reversing mill or train must be erected.
Another possibility is to provide a multi-stand, for instance, a four or five-stand tandem train, which works economically starting with an output of 1 million tons per year. In so-called "mini-steel plants," which have an output of approximately 700,000 tons per year, the use of a four-stand tandem train for cold rolling strips is not worthwhile for economic reasons. The single-stand reversing mill or train for cold rolling strips however is inadequate for rolling the entire output of a "mini-steel mill" into cold rolled strips. The solution of providing two single-stand reversing trains in one single "mini-steel plant" is also cost intensive because the two trains are not operating at full load capacity and since relatively high installation invention must be undertaken for the two trains.
Another disadvantage of a single reversing stand, compared to multi-stand installations, is the inability to use a roughened in the last pass.
It is therefore an object of the invention to provide a cold rolling mill for a widely distributed assortment of strip-shaped rolling material.
Another object of the invention is to provide a reversing compact installation for cold rolling strip-shaped rolling material which has a yearly capacity of approximately 700,000 tons of cold rolled strip and which is thus optimally suited for use in "mini steel plants"--i.e. in production range between a reversing stand and a tandem train.
Yet another object of the invention is to assure that work rolls with variable diameters can be used to assure optimum pass reductions.
A further object of the invention is to permit use of roughened work rolls for the last pass.
Additionally, an object of the invention is to simplify and speed up the change of work rolls in case of friction driven work rolls, which again favors a higher throughout.